问题
解答题
解方程:(x+2)(x+3)=20
答案
∵x2+5x+6-20=0
∴x2+5x-14=0
∴(x-2)(x+7)=0
解得x1=-7,x2=2.
解方程:(x+2)(x+3)=20
∵x2+5x+6-20=0
∴x2+5x-14=0
∴(x-2)(x+7)=0
解得x1=-7,x2=2.
A. Chinese and physics B. Math and art C. English and Chinese D. history and P.E. ( )2. She finishes her morning lessons at_______. A. 7:30a.m. B. 11:45 a.m. C. 1:30 p.m. D. 3:45p.m. ( )3. She has noon break ______. A. from 11:45 a.m. to 1:30 p.m. B. from 3:05p.m. to 3:45p.m. C. from 10:30 a.m. to 11:00a.m. D. from 11:00a.m. to 2:00 p.m. ( )4. She has_________ geography lessons in a week. A. two B. three C. four D. five ( )5. She has_______ subjects in all(共计). A. seven B. nine C. eleven D. thirteen |